1. Field of the Invention
The present invention relates to the production of solutions of tertiary butyl hydroperoxide (TBHP) in tertiary butyl alcohol (TBA) which are highly concentrated in TBHP, i.e. 65 wt. % or higher.
2. Description of Prior Art
Methods are known for the production of TBHP by the molecular oxygen oxidation of isobutane at elevated temperature and pressure. In this regard, attention is drawn to U.S. Pat. No. 2,845,461 of Winkler, et al., to U.S. Pat. No. 3,478,108 of Grane and to U.S. Pat. No. 4,408,081 of Foster, et al.
In general, as a result of the molecular oxygen oxidation of isobutane as described in literature such as above-cited, there is formed a reaction mixture comprised of unreacted isobutane, TBHP and TBA which is also formed during the oxidation reaction and/or used as a stabilizing additive. U.S. Pat. No.4,128,587 shows the addition of TBA to the isobutane feed to such an oxidation zone. Isobutane, which has a normal boiling point much lower than that of either TBHP or TBA, can be readily separated from the oxidation mixture. However, the separation of TBHP and TBA is much more difficult and hazardous.
In many instances, the relative amounts of TBHP and TBA which are produced result in oxidation product mixtures comprised of 55% by weight or less of TBHP based on the total of TBHP plus TBA after removal of unreacted isobutane. In certain applications it is advantageous to employ solutions of TBHP in TBA which are more highly concentrated in TBHP, especially solutions which comprise 65 wt. % or more TBHP based on the total of TBHP plus TBA. However, normal distillation procedures are hazardous since at higher liquid concentrations of TBHP, distillate vapor tends to involve explosive concentrations of TBHP.
U.S. Pat. No. 3,427,229 of Herzog shows use of a fluxing agent to prevent accumulation of TBHP in the vapors removed from an epoxidation reactor. It is indicated that hydroperoxide decomposition may present safety problems; see column 2, lines 1-4.
Harvey U.S. Pat. No. 3,449,217 teaches the recovery of TBHP from isobutane oxidation mixtures by a procedure involving neutralization, dilution with water, and distillation at reduced pressure with a water/TBHP azeotrope recovered overhead, condensed and phase separated.
Worrell, et al. U.S. Pat. No. 3,864,216 describes purifying TBHP from isobutane oxidation mixtures by neutralization, water addition and atmospheric pressure distillation with the use of a diluent gas.
Worrell U.S. Pat. No. 4,257,852 shows distillation of aqueous TBHP streams in an apparatus having flame arresting packing.
For certain applications, it would be useful to distill an isobutane oxidate reaction mixture comprised of TBHP and TBA without the addition of materials such as water in order to produce a mixture of TBHP and TBA comprised of 65 wt. % TBHP or more while avoiding flammability and explosion hazards during the distillation.